Alcohol-impaired driving (AID) continues to be a significant public health problem. For the past several years, the proportion of AID fatal crashes has remained at about one-third of all fatal crashes. Evidence from countries outside the United States (US) shows that lowering the illegal blood-alcohol concentration (BAC) standard below 0.08% is an effective way to lower the incidence of alcohol AID and the associated crashes, deaths, and injuries. The broad, overarching objective of this research project is to support legislation that has a high probability of reducing the incidence of AID in the US, thereby reducing the number of deaths and injuries caused by AID-related crashes. This objective will be achieved through completion of three specific aims. The first is to determine the feasibility of successively lowering the BAC standard for US drivers below 0.08% g/dl. This aim will be addressed through structured interviews with representatives from organizations that might be impacted by or have an impact on lowering the illegal BAC level for AID, such as the National Conference of State Legislatures, Council for State Governments, Association of Chiefs of Police; National Sheriff's Association; American Association of State Troopers; Governor's Highway Safety Association; Association of Prosecuting Attorneys; National Association of Criminal Defense Lawyers; American Judges Association; national Alcoholic Beverage Control Association; National Restaurant Association; US Department of Transportation; National Association of Insurance Commissioners; US Health and Human Services; US Substance Abuse and Mental Health Services Administration, US Department of Justice, Mothers Against Drunk Driving; and Students Against Drunk Driving. The second aim is to determine the potential benefits of successively lowering the BAC standard for US drivers below 0.08% g/dl. This aim will be addressed quantitatively through analyses of crash and injury reduction that have been reported in other countries that have implemented a lowering of the legal BAC level, such as Japan, many European countries, and Australia. Cost-benefit analyses will be conducted by applying the estimated reductions to current US data. Both direct monetary and nonmonetary quality of life costs in the US will be included in the cost analysis. The third aim is to determine the acceptability among US drivers of successively lowering the BAC standard below 0.08% g/dl. This aim will be completed through a nationwide questionnaire of currently licensed adult drivers. The following topics will likely be included: the acceptability of various reductions in the BAC legal limit; knowledge of current AID laws and sanctions; experiences with AID (both as a passenger and as a driver); attitudes toward AID and alcohol consumption; driving and violation history; perceived risk of being arrested for AID; legal responsibility for AD crashes (e.g., driver, those who served the alcohol, alcohol manufacturer); and demographics. The results should be useful for states that want to reduce unintentional AID-related death and injuries by lowering the illegal BAC limit for driving.